Thank you for reporting the issue.
Unfortunately, I couldn't replicate the case, so we need to investigate more. More details will be helpful.
This kind of issue can happen if something blocks access to sync servers (antivirus or firewall rule maybe).
First, please try to update to the latest browser version or uninstall/install the latest version.
Also, please check what happens inside secure://sync-internals/.
If sync is enabled, this page should reflect it. On the first, 'About' page please check values for "transport state", "sync feature enable", "auth error", "sync protocol log", "type info".
If you want to share screenshots of that page, please make sure it includes only requested values, not other data, that might be sensitive.
Thank you!